Various types of sterile packing and stents are used in the medical and surgical fields for keeping tissues apart or preventing adhesion. Such uses include, but are not limited to, nasal packing and sinus stents, packing for inner ear surgery, tympanoplasty, exostosis, orbital decompression, as well as various orifice restenosis prevention uses. Personal uses such as tampons, bandaging and the like also involve sterile packing materials.
Such packing and stents have been made from gauzes, microfibers, nonfibrous expandable packing, such as tampons, and the like. These types of packing are not bioresorbable and can cause injury or discomfort upon removal, as well as causing toxic shock syndrome if left internally for more than a day or two.
In an attempt to prevent such reactions, while continuing to prevent adhesion and tissue necrosis, resorbable packing and stent devices have been developed. Such packing materials have typically included hyaluronic acid (HA), or salts of hyaluronic acids, which are naturally occurring mucopolysaccharides found in various body fluids and connective tissues. Thus, HA is biocompatible. It has been adapted for use as a surgical aid to prevent tissue contact and adhesion formation. However, HA has a very high solubility, and thus poor liquid absorption, and tends to quickly disperse when exposed to such liquids. This reduces HA materials' effectiveness in areas such as surgical wounds which exude blood and other fluids. Crosslinking has created somewhat insoluble HA materials. Further, other biocompatible materials such as polysaccharides, especially methylcellulosic materials have been combined with the hyaluronic acid to produce packing materials which are resorbable but are also insoluble and have a longer in-vivo residence time before they dissolve into gels and are absorbed by the body tissues. These materials also have increased fluid absorption capabilities. Such materials stop bleeding only by effect of compression and packing and do not have any inherent hemostatic properties.
Collagen is also known for use in the medical field; it is a major protein constituent of connective tissue and is widely used in medical and surgical applications such as sutures, grafts and surgical prostheses. Typical sources include calfskin, bovine Achilles tendons, cattle bones, porcine tissue, human cadaver tissue, and rat tails. Collagen, as an animal protein, is bioresorbable, even when crosslinked to reasonable levels. Collagen is available in a variety of forms including powders and fibrils, and in aqueous solution. Collagen may be provided in insoluble or soluble forms.
It has now been discovered that a flexible bioresorbable foam for packing, post-operative use, and other medical uses may be created having both hemostatic properties and a variable preselectable resorption time (also known as an in-vivo residence time). The foam is formed from a blend of collagen and hyaluronic acid or derivative thereof.